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-rw-r--r--0004-x86-setup-Move-trim_snb_memory-later-in-setup_arch-t.patch87
1 files changed, 87 insertions, 0 deletions
diff --git a/0004-x86-setup-Move-trim_snb_memory-later-in-setup_arch-t.patch b/0004-x86-setup-Move-trim_snb_memory-later-in-setup_arch-t.patch
new file mode 100644
index 00000000000..8a8e4d194cc
--- /dev/null
+++ b/0004-x86-setup-Move-trim_snb_memory-later-in-setup_arch-t.patch
@@ -0,0 +1,87 @@
+From c4b5e4bc8317ccb0a822429d87288d9f90453a04 Mon Sep 17 00:00:00 2001
+From: Mike Rapoport <rppt@linux.ibm.com>
+Date: Tue, 13 Apr 2021 21:08:39 +0300
+Subject: [PATCH 4/8] x86/setup: Move trim_snb_memory() later in setup_arch()
+ to fix boot hangs
+
+Commit
+
+ a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
+
+moved reservation of the memory inaccessible by Sandy Bride integrated
+graphics very early, and, as a result, on systems with such devices
+the first 1M was reserved by trim_snb_memory() which prevented the
+allocation of the real mode trampoline and made the boot hang very
+early.
+
+Since the purpose of trim_snb_memory() is to prevent problematic pages
+ever reaching the graphics device, it is safe to reserve these pages
+after memblock allocations are possible.
+
+Move trim_snb_memory() later in boot so that it will be called after
+reserve_real_mode() and make comments describing trim_snb_memory()
+operation more elaborate.
+
+ [ bp: Massage a bit. ]
+
+Fixes: a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
+Reported-by: Randy Dunlap <rdunlap@infradead.org>
+Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Tested-by: Randy Dunlap <rdunlap@infradead.org>
+Tested-by: Hugh Dickins <hughd@google.com>
+Link: https://lkml.kernel.org/r/f67d3e03-af90-f790-baf4-8d412fe055af@infradead.org
+---
+ arch/x86/kernel/setup.c | 20 +++++++++++++++-----
+ 1 file changed, 15 insertions(+), 5 deletions(-)
+
+diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
+index 282d572e49af..7d466f51be1f 100644
+--- a/arch/x86/kernel/setup.c
++++ b/arch/x86/kernel/setup.c
+@@ -634,11 +634,16 @@ static void __init trim_snb_memory(void)
+ printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
+
+ /*
+- * Reserve all memory below the 1 MB mark that has not
+- * already been reserved.
++ * SandyBridge integrated graphics devices have a bug that prevents
++ * them from accessing certain memory ranges, namely anything below
++ * 1M and in the pages listed in bad_pages[] above.
++ *
++ * To avoid these pages being ever accessed by SNB gfx devices
++ * reserve all memory below the 1 MB mark and bad_pages that have
++ * not already been reserved at boot time.
+ */
+ memblock_reserve(0, 1<<20);
+-
++
+ for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
+ if (memblock_reserve(bad_pages[i], PAGE_SIZE))
+ printk(KERN_WARNING "failed to reserve 0x%08lx\n",
+@@ -747,8 +752,6 @@ static void __init early_reserve_memory(void)
+
+ reserve_ibft_region();
+ reserve_bios_regions();
+-
+- trim_snb_memory();
+ }
+
+ /*
+@@ -1082,6 +1085,13 @@ void __init setup_arch(char **cmdline_p)
+
+ reserve_real_mode();
+
++ /*
++ * Reserving memory causing GPU hangs on Sandy Bridge integrated
++ * graphics devices should be done after we allocated memory under
++ * 1M for the real mode trampoline.
++ */
++ trim_snb_memory();
++
+ init_mem_mapping();
+
+ idt_setup_early_pf();
+--
+2.32.0
+